Chemistry 2e

Citation

Flowers, P., Theopold, K., Langley, R., & Robinson, W. R. (2019). Chemistry 2e (2nd ed.). OpenStax. Free official edition: https://openstax.org/details/books/chemistry-2e

Chapter Summary

Chemistry 2e is OpenStax's text for the two-semester general chemistry course, about 1,200 pages in the PDF: 21 chapters, thirteen data appendices (A–M) and an answer key. Every chapter follows the same pattern: a short opening scenario, numbered sections that begin with learning objectives, worked Examples each followed by a "Check Your Learning" problem, then key terms, key equations, a section-by-section summary and exercises.

Chapter 1: Essential Ideas

The course opens with the scope and methods of chemistry, the classification and properties of matter, and then measurement: SI units, uncertainty and significant figures, accuracy and precision, and dimensional analysis for unit conversions.

Chapters 2–4: Atoms, Molecules, and Ions; Composition of Substances and Solutions; Stoichiometry of Chemical Reactions

Chapter 2 traces atomic theory from Dalton to Rutherford and Chadwick, then covers isotopes, formulas, a first look at the periodic table, ionic and molecular compounds and nomenclature. Chapter 3 introduces the mole, empirical and molecular formulas, molarity and other concentration units. Chapter 4 balances equations, classifies reactions as precipitation, acid–base or redox, and applies stoichiometry to limiting reactants, yields, titration and gravimetric analysis.

Chapter 5: Thermochemistry

Energy, heat and work, specific heat and calorimetry, then enthalpy: standard enthalpies of formation and Hess's law. The fuller thermodynamics of entropy and free energy is deferred to Chapter 16.

Chapters 6–8: Electronic Structure and Periodic Properties of Elements; Chemical Bonding and Molecular Geometry; Advanced Theories of Covalent Bonding

Chapter 6 moves from electromagnetic radiation, blackbody radiation and the photoelectric effect to the Bohr model, the Schrödinger equation and quantum numbers, electron configurations and periodic trends. Chapter 7 covers ionic and covalent bonding, electronegativity, Lewis structures, formal charge and resonance, bond strengths (including a Born–Haber cycle) and VSEPR shapes and polarity. Chapter 8 adds valence bond theory, hybridization, multiple bonds and molecular orbital theory, which it uses to explain why oxygen is paramagnetic.

Chapters 9–11: Gases; Liquids and Solids; Solutions and Colloids

The states of matter: gas pressure, the gas laws and ideal gas law, gas stoichiometry and partial pressures, effusion and diffusion, kinetic-molecular theory and non-ideal behaviour (Chapter 9); intermolecular forces, properties of liquids, phase transitions, phase diagrams and crystalline solids, including unit cells and X-ray diffraction (Chapter 10); and dissolution, electrolytes, solubility, colligative properties and colloids (Chapter 11).

Chapter 12: Kinetics

Reaction rates and their controlling factors, experimental rate laws, integrated rate laws and half-lives, collision theory and the Arrhenius equation, mechanisms and catalysis.

Chapters 13–15: Fundamental Equilibrium Concepts; Acid-Base Equilibria; Equilibria of Other Reaction Classes

Chapter 13 defines the reaction quotient and equilibrium constant, applies Le Châtelier's principle and sets up the ICE-table method for calculations. Chapter 14 builds Brønsted–Lowry acid–base chemistry on it: pH and pOH, relative strengths and ionization constants, salt hydrolysis, polyprotic acids, buffers and titration curves. Chapter 15 extends equilibrium to solubility products, Lewis acids and bases with complex-ion formation constants, and coupled equilibria.

Chapters 16–17: Thermodynamics; Electrochemistry

Chapter 16 introduces spontaneity, entropy (as microstates and as reversible heat), the second and third laws and Gibbs free energy, connecting free energy to the equilibrium constant. Chapter 17 reviews redox chemistry and then covers galvanic cells, standard electrode potentials, the links between cell potential, free energy and equilibrium, the Nernst equation, batteries and fuel cells, corrosion and electrolysis.

Chapters 18–19: Representative Metals, Metalloids, and Nonmetals; Transition Metals and Coordination Chemistry

The descriptive chapters. Chapter 18, with twelve sections, surveys main-group periodicity and then the occurrence, preparation and compounds of the representative metals, metalloids and nonmetals from hydrogen to the noble gases. Chapter 19 treats transition metals, coordination compounds (ligands, chelates, isomerism) and their spectroscopic and magnetic properties through crystal field theory.

Chapters 20–21: Organic Chemistry; Nuclear Chemistry

Chapter 20 is a single-chapter survey of organic compounds: hydrocarbons, alcohols and ethers, carbonyl compounds, and amines and amides. Chapter 21 covers nuclear stability and binding energy, nuclear equations, radioactive decay and half-lives, fission and fusion, uses of radioisotopes and the biological effects of radiation.

Key Concepts

Chapters 1–5: Foundations, Stoichiometry and Thermochemistry

• Mole and molar mass: the unit linking grams to numbers of atoms and molecules.
• Limiting reactant and percent yield: the reactant that runs out first fixes the theoretical yield, against which the actual yield is compared.
• Hess's law: enthalpy changes add along any path, so reaction enthalpies can be computed from tabulated enthalpies of formation.

Chapters 6–8: Atoms and Bonding

• Quantum numbers and electron configurations: the description of electrons in atoms that explains periodic trends in size, ionization energy and electron affinity.
• VSEPR theory: predicting molecular shape from the number of regions of electron density around a central atom.
• Molecular orbital theory: bonding and antibonding combinations of atomic orbitals, used to explain bond order and magnetism.

Chapters 9–12: States of Matter, Solutions and Kinetics

• Ideal gas law: PV = nRT, with Boyle's, Charles's, Amontons's and Avogadro's laws as special cases.
• Intermolecular forces: dispersion forces, dipole–dipole attractions and hydrogen bonds, which account for boiling points and solubility.
• Rate law and activation energy: the experimentally determined dependence of rate on concentration, and the energy barrier described by the Arrhenius equation.

Chapters 13–17: Equilibrium, Thermodynamics and Electrochemistry

• Equilibrium constant and Le Châtelier's principle: the composition of an equilibrium mixture and how it shifts when disturbed.
• Buffers: mixtures of a weak acid and its conjugate base that resist pH change, treated with the Henderson–Hasselbalch equation.
• Gibbs free energy: the state function whose sign decides spontaneity at constant temperature and pressure and which is tied to K and to cell potential.

Chapters 18–21: Descriptive, Organic and Nuclear Chemistry

• Crystal field theory: the splitting of d orbitals by ligands, which explains the colour and magnetism of complexes.
• Binding energy and half-life: the energy released by the mass defect, and the first-order decay that every radioisotope follows.

Critical Analysis

Strengths

• Consistent worked-example design. Close to three hundred numbered Examples set out a solution step by step and end with a Check Your Learning problem and its answer, so each skill is practised where it is taught.
• Complete standard coverage at no cost. The table of contents follows the usual two-semester sequence from measurement to nuclear chemistry, and the book is free online and as a PDF under a CC BY-NC-SA licence, which also lets instructors reorder or remix chapters, as the preface notes.
• Built-in reference data. The appendices supply what the exercises need: thermodynamic data, ionization constants, solubility products, formation constants, standard electrode potentials and half-lives, plus an Essential Mathematics appendix on exponential notation, logarithms and the quadratic formula.
• Context features. 44 Chemistry in Everyday Life boxes, 19 How Sciences Interconnect boxes and 10 Portrait of a Chemist profiles (Linus Pauling and Rosalind Franklin among them) add context without interrupting the core material.

Limitations

• Algebra-based by design. Where calculus would enter, the book states results instead: slopes of concentration curves are said to be beyond the scope of the chapter, and integrated rate laws are presented as outcomes of an integration that is not shown. Students who want derivations need a different kind of text.
• Thin organic chemistry. Organic chemistry is a single four-section chapter organised by compound class, introducing substitution and addition reactions by type rather than by mechanism; it is a preview, not preparation for an organic course.
• Answers only for odd-numbered exercises. The answer key covers odd-numbered end-of-chapter exercises; even-numbered answers are reserved for instructors.
• Some dated context. Some context material relies on older data; the thermochemistry chapter, for example, opens with US energy-use figures from 2012.

Where It Fits in the Course

Among the general chemistry books on this list, Chemistry 2e is the free, openly licensed option for the standard algebra-based sequence. Its closest commercial counterparts are Brown and colleagues' Chemistry: The Central Science and Petrucci and colleagues' General Chemistry: Principles and Modern Applications, comprehensive texts that cover a similar sequence; Chemistry 2e can replace either, or be used alongside one for extra explanations and worked examples.

Two other books on the list suit students who want more. Atkins and colleagues' Chemical Principles is calculus-based and builds the subject from physical principles, supplying the derivations Chemistry 2e leaves out. Keeler and Wothers's Chemical Structure and Reactivity abandons the usual split into organic, inorganic and physical chemistry and takes orbital theory, thermodynamics and kinetics further; it is a natural next step for chemistry majors.

How to Use This Book

The book is written for first-year students in a two-semester general chemistry course. School algebra, exponents and scientific notation are the working prerequisites; Appendix B reviews them, and Chapter 1 teaches the dimensional analysis used everywhere else.

A typical division, following the chapter order:

• First semester: Chapters 1–10 (measurement, atoms, stoichiometry, thermochemistry, electronic structure, bonding, gases, liquids and solids).
• Second semester: Chapters 11–17 (solutions, kinetics, the three equilibrium chapters, thermodynamics, electrochemistry). Chapters 14 and 15 reuse Chapter 13's methods throughout.
• Optional or selective: Chapters 18–21. Chapters 18 and 19 are descriptive surveys to read selectively; Chapter 19 is useful before an inorganic course, Chapter 20 before organic chemistry, and Chapter 21 if the course covers nuclear chemistry.

For self-study, work every Check Your Learning problem, then the odd-numbered exercises against the answer key. Revisit Chapter 5 before Chapter 16 and Section 4.2 before Chapter 17, since the book returns to those topics. The Link to Learning items point to PhET simulations and other interactive material; the simulations on atomic structure, the ideal gas law, states of matter and reaction rates are worth using, and some end-of-chapter exercises are built around them.

Edition and Sources

This guide is based on Chemistry 2e (OpenStax, original publication February 2019; senior contributing authors Paul Flowers, Klaus Theopold, Richard Langley and William R. Robinson), read in the official free PDF from https://openstax.org/details/books/chemistry-2e (current printing, CC BY-NC-SA 4.0). It draws on the preface, the full table of contents and appendices list, and for all 21 chapters the opening introduction, every section heading and the section-by-section summary, with selected sections read in more detail.